What is a garden annexe?

A garden annexe is a single-storey building in the garden with its own living space, bathroom and often a kitchenette, used by relatives, older children or guests. Unlike a garden room, it is built as habitable accommodation with foundations, insulation and services.
How much does a garden annexe cost in Dunoon?
In Dunoon, a garden annexe typically costs £1,750–£2,700 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £61,000–£94,500. Island and remote projects usually cost more than this guide because of shipping, travel and accommodation. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £42,000–£65,000 |
| Typical project (35 m²) | £61,000–£94,500 |
| Larger project (49 m²) | £86,000–£132,500 |
| Rate per m² | £1,750–£2,700 |
What moves the price most:
- Heating type
- Access for materials
- Kitchen and bathroom
- Drainage connection distance
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a garden annexe in Dunoon?
Approvals for a garden annexe in Dunoon follow the rules for Scotland. In Scotland an annexe with living accommodation needs planning permission and a building warrant.
In Scotland a building warrant is needed before work starts on most extensions, loft conversions and conversions. It is issued by the council’s building standards service. When the work is finished, a completion certificate is submitted and accepted by the council after inspection.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical garden annexe we handle:
- Planning drawings and application
- Glazed doors and windows
- Building control sign-off
- Insulated walls and roof
- Electrics and heating
- Foundations and drainage connections
How long does it take?
Expect 10 to 16 weeks on site. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Dunoon
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Projects in Dunoon are taken on by arrangement. We confirm availability first, and any travel or accommodation costs are shown separately in the quote.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about garden annexes in Dunoon
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
Do I need planning permission for a garden annexe in Dunoon?
In Scotland an annexe with living accommodation needs planning permission and a building warrant.
Who approves a garden annexe in Dunoon?
Planning matters in Dunoon go to the council covering your address, and the work needs a building warrant. We prepare and submit the applications for you.
How much does a garden annexe cost in Dunoon?
In Dunoon, a garden annexe typically costs £1,750–£2,700 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £61,000–£94,500. Your fixed price depends on the survey and drawings.
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.
Will council tax apply?
Annexes can be banded separately, though discounts or exemptions apply in some cases when occupied by family. Check with your council.
